The field of the invention is emulsions of silicone fluids in water and the present invention is particularly concerned with an improvement in the method of making emulsions of dimethyl silicone fluids.
The state of the art of dimethyl silicone fluids and emulsifying methods therefore may be ascertained by reference to the Kirk-Othmer "Encyclopedia of Chemical Technology", 2nd Edition, Volume 18 (1959), pp. 221-260 under the Section Silicones, particularly pp. 237-241 where dimethyl silicone fluids are disclosed, and p. 249 where emulsions of silicone fluids are disclosed and British Pat. Nos. 808,193 and 915,787 and U.S. Pat. No. 2,755,194 where emulsifying methods are defined. These references are incorporated herein.
Water-dilutable oil-in-water emulsions are an especially preferred form of using the silicone oils or fluids. In this form, they are employed, for example, to render materials hydrophobic, for defrothing purposes, for the application of thin films for release purposes, for lustering, for increasing the slip and for improving the hand of textile materials. As is known, great difficulties are encountered in the production of finely dispersed, aqueous silicone oil emulsions (see "Ullmanns Enzyklopaedie der technischen Chemie" [Ullmann's Encyclopedia of Technical Chemistry] third edition, 1964, vol. 15, p. 783, fifth paragraph), the disclosure of which is incorporated herein.
Although several emulsifying methods are known from British Pat. Nos. 808,193 and 915,787 and U.S. Pat. No. 2,755,194, column 2, these operate with the aid of homogenizing devices and/or with the use of solvents in addition to the emulsifiers. In spite of the expensive manufacturing process, these emulsions are generally of insufficient stability with regard to shelf life. Furthermore, these emulsions, due to their solvent content, are poorly or not at all suitable for certain usages, such as, for example, for textile preparations.